Deliverability
What is IP Reputation?
A mailbox provider's trust score for the specific IP address that delivers your mail.
IP reputation is the trust a receiver assigns to a sending IP based on its history: volume patterns, complaint and bounce rates, spam-trap hits, and any listings on RBLs or blacklists. It is established through gradual IP warming and can be shared across many senders in a pool or dedicated to one sender. It works alongside, and is increasingly secondary to, domain reputation.
Why it matters for cold email
On the shared sending pools common in cold email, a neighbor's bad behavior can drag down the IP you send from, and a fresh dedicated IP starts with no reputation and must be warmed. Monitoring blacklists and complaint rates on your sending IPs prevents one bad run from blocking everyone on the address.
Related terms
Stop guessing at deliverability.
Scheduler Zero handles authentication, warmup, and sender reputation so your cold email lands in the inbox, not the spam folder.